In 1780, the 12th Earl of Derby instituted an annual horse race at the Epsom Downs near Epsom, England. It was called the Epsom Derby, so named from his title. This earldom is so named, of course, for Derby, the shire or town in England. For my readers outside of the UK, Derby is well north of London and Epsom is a bit south of the capital. So, the race was not run in Derby but is named, ultimately, after Derby.
Stateside, the derby lives on most famously in the Kentucky Derby. Indeed, Epsom Downs notes more than 140 races worldwide have adopted the toponym–not to mention the borrowings seen in roller derbies and demolition derbies. The Kentucky Derby itself is famous for its hats, although the derby hat, American English for the bowler hat, is no longer at the peak of its popularity, if you will.
The bowler is named for the surname of its creator, so why the US usage of derby that emerges in the 19th century? Etymologists speculate that the derby is perhaps named for those worn by the “famous sportsmen, the Earls of Derby” (Partridge) at the races.
Whence the name Derby?
The jury is out, but their verdict favors that Derby comes from the Old English Deorby (also recorded as Deoraby, and much later, the variant Darby). If this is so, the place name may be a compound of deor (“deer”) and by, from the Scandinavian byr, a “village” or “town.” You might recognize this by in bylaw, a local law, from the Old Norse. By the by, the preposition by was also used in place names, so the English by and Scandinavian by experienced some cross-influence.
If we hunt down deer further, we find generic Germanic roots for “animal.” If we run deeper into the woods, we find the Proto-Indo-European *dheusom, “breathing creature.” The base *dheu is hypothesized to mean “breath,” “smoke,” and “dust.” By‘s way goes back to a Germanic root *bu, “to dwell,” related to the Proto-Indo-European *bheu, “to dwell, “to grow,” and that be-all and end-all, “to be.”
So, if you’re at the Derby, live it up. No, literally, live it up and enjoy the Kentucky “Breath-Be.” OK, I might be chomping at the etymological bit, but run with it, will you?